Doradla in his research note said that his checks of Verizon's sales channel indicate that for the June quarter, the iPhone slipped as the top-selling device on Verizon's network to the No. 2 spot. The Motorola Droid Razr Maxx has replaced the iPhone at Verizon as the top-selling smartphone, according to Doradla.

This is a big deal since the iPhone has been the top-selling smartphone at Verizon since it went on sale there in February 2011. In fact, the iPhone has been the leading smartphone for all three major wireless carriers offering the device.

Doradla attributes the slip in sales to the fact that Verizon has been aggressively marketing its 4G LTE devices. In particular, the company has been pushing the Droid Razr Maxx. In fact, in May CNNMoney published a story about Verizon customers who had gone into retail locations wanting an iPhone being talked into buying an LTE Droid instead.

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Verizon representatives have said that they're just trying to match customers with the right devices. But it would make sense for the company to push 4G LTE devices over the iPhone. For one, Verizon would like to migrate customers from the 3G network to 4G, since it's more cost-effective over the life of that customer. Second, the company has to pay a hefty subsidy for the iPhone. And the subsidies for devices such as the Droid Razr Maxx are much less.

Still, Doradla says in his note that he believes that Apple will get its mojo back once the next version of the iPhone is released. This new version, which is expected this fall, will likely support 4G LTE too. And once that happens, customers, who have already heard all the benefits of the speedier network, will likely flock to the new iPhone.

"While we acknowledge the increased competitive landscape from 4G devices (and the iPhone 4S is not 4G), we are not worried [about] Apple conceding its top position in North America any time soon," he said in the note. "We believe the anticipated launch of a 4G device from Apple this fall will be an important catalyst for the company as consumers upgrade their phones, and we expect the company to once again maintain its top position at all operators (including Verizon Wireless)."

Meanwhile, Michael Walkley, analyst with Canaccord Genuity, told AppleInsider that his check of Verizon's retail channel indicate that the iPhone has not slipped from No. 1. He said that the Droid Razr is "gaining ground" against the iPhone, but he added that it hasn't yet caught up to the iPhone. In his own research, he reports that the iPhone 4S is still the top-selling phone at Verizon. And it's still the No. 1 phone sold at AT&T and Sprint as well for the first half of 2012.